This invention relates to tissue examination, and in particular to detecting foreign structures in, e.g., breast tissue.
One traditional way of examining breast tissue to detect foreign structures such as lumps is to palpate the breast manually. For example, the patient firmly presses on the breast with three fingers while moving the fingers in a circular palpating motion. Typically, such manual breast self-examinations can detect lumps as small as a few centimeters in diameter.
Instruments for electronically examining the breast are available. One such instrument includes an array of pressure sensors which is pressed against the breast. Each pressure sensor in the array generates an electrical signal proportional to the local pressure imposed on the sensor when the array is pressed against the breast. When adjacent sensors are positioned across the boundary of a lump within the breast tissue, the sensor that lies over the lump generates an electrical signal indicating the detection of greater local pressure than the adjacent transducer element, which is located over soft tissue alone. The instrument determines whether a lump is present by analyzing the differences between the electrical signals generated by the sensors.